1. Field of the Invention
The present invention primarily relates to manifold used for purposes such as refrigerant recovery in air-conditioning equipment.
2. Description of the Related Art
In conventional practice, manifolds having pressure gauges have been used in the work of refrigerant recovery and loading for vehicular air-conditioning equipment.
Such a manifold typically comprises a manifold body and valves for opening and closing passages inside the manifold body.
Passages inside the manifold body include a high-pressure-side passage, a low-pressure-side passage, a recovery-side passage, a vacuum-suction-side passage, a purging passage, and a common passage via which these passages communicate. A high-pressure-side valve at least is provided to the high-pressure-side passage, and a low-pressure-side valve is provided at least to the low-pressure-side passage.
In times such as the height of summer in particular, post-diagnostic cool checks are performed on a cooler unit.
In a manifold having the above configuration, high-pressure liquid refrigerant and compressor oil tend to remain in the spaces up to the connecting parts (high-pressure-side quick joint and the like) leading from the high-pressure-side valve and the high-pressure-side pressure gauge to the high-pressure-side hose after a post-diagnostic cool check is used on the cooler unit.
The residual liquid refrigerant and compressor oil make it impossible to maintain the appropriate regulated amount of air-conditioning refrigerant when a fixed amount is loaded, and as a result, the air conditioning will not be consistently effective.
A known example of a configuration that can resolve the problem of residual liquid refrigerant and compressor oil is one in which, e.g., a three-way joint is connected with a gauge manifold either directly or via a straight joint between a high-pressure hose and a low-pressure hose, and the connection port of the high-pressure valve and the left and right connection ports of the three-way joint attached to the gauge manifold are fastened by flare nuts via copper valves, hoses, or the like (for example, see Patent Document 1).